Simplify the following expression: $k = \dfrac{25f + 30g}{30f - 15h} - \dfrac{30h}{30f - 15h}$ You can assume $f,g,h \neq 0$.
Solution: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{25f + 30g - (30h)}{30f - 15h}$ $k = \dfrac{25f + 30g - 30h}{30f - 15h}$ The numerator and denominator have a common factor of $5$, so we can simplify $k = \dfrac{5f + 6g - 6h}{6f - 3h}$